Hydraulic pump or motor for hydraulic transmissions



June 20, 1933. R. J. SMITH I 4 1,914,622

HYDRAULIC PUMP OR MOTOR FOR HYDRAULIC TRANSMISSIONS Filed June 24, 1930 2 Sheets-Sheet 1 R. J. SMITH June 20, 1933.

HYDRAULIC PUMP 0R MOT OR FOR HYDRAULIC TRANSMISSIONS Filed June 24, 1930 '2 Sheets-Sheet 2 lltfa Patented June 20, 1933 UNITD. s

en n RALPH JOHN SETH, OF DERBY, ENGLAND, ASSIGNOR OF ONE-THIRD '10 CHARLES ANDREW NEWTON, F DERBY, ENGLAND, AND ONE-THIRD TO REGINALD CLAUDE ROE, OF BOCHDALE, ENGLAND HYDRAULIC PUMP OB MOTOR FOB HYDRAULIC TRANSMISSIONS Application filed June 24, 1930, Serial No. 468,505, and in Great Britain August 6,1929.

and located in radial pockets in a fixed disc. or ring concentric with the axis of rotation of the excentric ring, and fluid distribution means for the divisions of the space between the excentric ring and the disc or ring and for the pockets in which the rollers reciprocate.

The invention further comprises the im proved combinations and arrangements of parts hereinafter described and claimed.

Referring to the accompanying explanatory drawings Figure 1 is a longitudinal sectional elev ation of a combined pump and motor unit constructed and arranged in-one convenient form in accordance with my invention.

Figure 2 is a cross sectional elevation on the line A B of Figure 1.

Figure 3 is a cross sectional elevation on the line C D of Figure 1.

Figures 4, 5 and 6 are detail views of the crank pin by which the valve of the motor is operated. v

-Figure 7 is a detail face view of the valve sealing ring to be hereinafter described.

Figure,8 is a side view and Figure 9 a front view of the means by which the rollersare anchored run. I

Figure 10 1s a detail sectional View showto the ring upon which they ing a valve controlled passageto a division of the space around the excentrically movingJring.

Figure 11 is a detail sectional view'of the U shaped sprin ring drawn. to a larger scale. a indicates t e pump operating shaft and b the motor driven shaft of the unit. The enlarged end of the shaft a is carried in bearings 0 and d and on its end face it has a crank pin 6 adapted to operate a valve ring 7 to be hereinafter more particularly described.

Within the enlarged end of the shaft 0 is arranged a part of of plunger 9 with inclined projecting ribs 11. at its opposite sides, said plunger being ,reciprocable by an arm 2' toothed pinion j, circular rack is, and crosspin m extending through an elongated slot n in the shaft a and through a slot in the end of the plunger 9. The inclined ribs h enter similarly inclined grooves h in segment shaped parts 0 keyed within the ring p which therefore acts in conjunction with the parts 0 as an excentric of a throw or degree of excentricity which can be varied by axial movement of the part 9 Within the shaft a. The excentric is rotated by the shaft a which has flat sides where it passes between the seg ment shaped parts 0 (see Figure 2). Around the ringp which will hereinafter be termed 0 the main excentric, are arranged hearing or antifriction shoes 9 and a floating ring 1''. Around the latter are arranged two rings 8 and t with a gap between them to receive the heads of members M which are of the form shown in side and front elevation in Figures 8 and 9 respectively.

The said members act as anchoring means for rollers 0 arranged one at each side of each member, so as to ensure that said rollers are in continuous rolling contact with the peripheral surface of the rings 8 and t. The method of securing the rollers upon the anchoring members will be understood by reference to the lower portion of the right hand side of Figure l Flanged bushings w are attached to the opposite sides of the member I of rotation of the main excentric p, that is with the axis of the shaft a. It will be seen that the rollers v in conjunction with the members u divide the space between the ring 2 and the rings 8, t on which the rollers a ride into a number of chambers 2, each of which will gradually increase in volume till a maximum is reached, when it Will decrease until a minimum is reached. The volume of each of the pockets y not occupied by the rollers v will also alternately increase and decrease. Passages at in the division wall 3 leadfrom the pockets to the face of the wall over which the valve ring f moves. Similar passages 6 (Figure 10) lead from the chambers 2 through the wall 3 to the face over which the valve ring f moves, the ends of the passages being shown at 5 and 6 in Figure 3,

,5 being the ports connected to the pockets 1/ and 6 the ports connected to the chambers 2. The inner edge of the valve ring f serves to cut off the ports 5 and 6 from communication with the suction space 7 and the outer edge of the valve serves to cut off the said ports from communication with the delivery or pressure space 8. The valve ring f has a sealing ring 9 at the back thereof and between the two rings is arranged a spring ring 10 of U shape in cross section (see Figure 11). Such spring ring serves both as a pressure seal for the division between the rings 7 and 9 and as a spring to maintain the valve in close contact with the ported face of wall 3 when there is no pressure in the space 8. When the pump is in operation, the pressure in the space 10a acts to hold both the ring 7 and the ring 9 in contact with the surfaces over which they move due to the rotation of the crank pin a. Figure 7 which illustrates the face of the ring 9 shows grooves 11 leading from the suction side of the ring to a groove 12 which divides the ring face into two portions. By this means, We limit the area of the ring 9 upon which the pressure fluid in the space 8 has to act to form a seal between the ring 9 and the fixed wall 13.

The motor or engine portion of the com- 7 plete unit is shown at the right hand side of Figure 1 and is similar to the pump unit but the excentric 12 upon the shaft 6 is a fixed excentric and the crank pin 6 which operates the valve ring f is capable of angular adjustment with relation to the shaft 1). Such adjustment is effected by moving the arm 14 which turns the toothed pinion 15 engaging the circular rack 16 into which project the ends of a pin 17 passing through the elongated slot 18 in the shaft 1) and a slot in the end of a rod 19 having a spiral thread thereon which threads into an internally threaded member 20 forming an extension of the spindle carrying the crank pin 6 If reference be made to Figures 4, 5 and 6, it will be seen that the crank pin 6 is turned of the shaft 6. When the part 19 is moved.

longitudinally it causes the part 20 to turn relatively to the shaft 6. If it be turned through an angle of 180, the valve fbecomes repositioned in relation to the main eXcentric p in such a way as to cause the motor to retate the shaft Z) in a reverse direction. If the crank pin is turned through. an angle of 90, the valve is in a neutral position and the motor remains at rest.

The general method of operation of the complete unit will be fairly self-evident. As the main excentric p is rotated by the shaft (1, the rollers v and the members at are reciprocated. When such rollers move into pockets, the fluid therein is delivered under pressure through the ports 4, 5 past the valve 7 and into the space 8. Simultaneously, the fluid which is being squeezed from chamber 2 between the rings a, t and the fixed rings 2 is being delivered through the ports 6 into the space 8. Vhere the rollers are moving out of pockets, fluid is being drawn into the latter from the space 7, past the valve f and through the ports 4 and 5. Similarly fluid is being drawn into the chambers 2 (which are increasing in volume) from the space 7 past the valve 7 and through the ports 6. The pressure fluid from the annular space 8 passes to certain of the pockets and of the chambers of the motor unit to effect propulsion of the excentric and the shaft 6 and other pockets and chambers are exhausting back into the space 7, all under the control of the valve 7.

If the unit be operating for the propulsion of a part which may over-run the pump portion (such as, for example, a motor vehicle when descending a hill) so that the delivery from the motor unit tends to increase the pressure in space 7 and correspondingly reduce the pressure in space 8, a valve 22 (which is normally closed by the pressure in 8) will relieve the pressure in 7. On the other hand, the motor unit may, by suitable manipulation of its valve 7, be set to oppose the pump unit so that under over-running conditions, the motor unit acts as a brake and resists the pressure in the space 8. Any excess pressure in the latter can be relieved by a spring loaded valve 23.

It will be noted that the ports 5 and 6 over which the valve ring f moves to place the.

ports into communication with the spaces 7 and 8, are at different radial distances. This is essential to ensure the correct sequence of openings and closings of the ports to the said spaces 7 and 8.

It will be noted that the space 8 around the with which they are in contact under all conditions of working.

At one end of'the combined unit, I provide a pipe .through which fluid'under pressure is'delivered into the unit and at the other end I provide a pipe 26 which is provided with a loaded valve (not shown) the pump are effected by varying the degree f pocket surfaces. Y

of excentricity of the main excentric 0 which varies the throw of the rollers in the pockets- 4 and the amount of alteration in the volume of the chambers 2 between the maximum and 2 minimum values. Variation in the speed of the motor can, of course, be obtained by adj usting the angular position of the crank pin 6 operating the valve f with relation to the main excentric p, but an adjustment of the angular position of the crank pin is usually only adapted for reversing the motor or for rendering it inoperative whilst the pump is still functioning. 6

Although the invention hasbeen described with reference to a combined pump and motor unit, it will be appreciated that the pump and the motor may form separate units cona propulsive effort in the pockets in which they move with a rolling motion over the I do not limit myself to the details of construction of my improved pump or motor,

but may vary the sameto suit, requirements.

What I claim is '1. In a variable speed gear, a rotary pump rollers riding upon said excentric ring, means constraining the rollers to remain continuously in rolling contact with the ring, a

' fixed disc or casing concentric withthe axis of rotation of said eccentric ring and having radial pockets therein in which saidrollers are located, ports in said pockets and also in i the divisions (between the several rollers) of the space between the excentric ring and the casing, and fluid dist 'ibution means controlling the fluid flow through said ports to and from said pockets and said spaces.

2. In a variable speed gear as claimed in claim 1, the arrangement of the rollers in the form of units each comprising two rollers, a member disposed between said rollers and upon which said rollers are mounted, two separate ring portions constituting said eccentric ring and having a gap therebetween, a ortion of said member proJecting through said gap and bearing upon the rear side of said ring portions so as to cause said rollers to remain in rolling contact with said ring.

3. In a variable speed gear, as claimed in claim 1, in which the control ports for the flow of fluid to and from the ports in the divisions of the spaces around the excentric ring and to and from the ports in the pockets are in two circles at difierent distances from a centre the provision of a ring type valve, and means imparting an excentric movement thereto-to cause the ring to move to one or other side of the ports so that the latter come within the ring, are covered by the ring or are outside thering.

4. In a variable speed gear as claimed in .claim 1, the provision of a division wall adjacent said fixed disc orcasing and having passages therethrough constituting part of said fluiddistribution means, a valve ring moving over the ported face of said division wallf remote from said fixed disc or ring, a fixed wall, a sealing ring arranged back .to back with said valve ring and abutting said fixed .wall and a U shaped spring ring between said valve ring and said sealing ring, said valve ring controlling the flow of fluid to and from the divisions of the spaces around the excentric ring and to and from said pockets.

5. In a variable speed gear, a rotary pump or hydraulic motor comprising an eccentric, a ring around said excentric antifriction means between said ring and said excentric, a two part ring around said ring, .rollers anchored to said two part ring so that they remain in continuous rolling contact therewith, a fixed disc or ring concentric with the axis of rotation of said eccentric and separated by a space from said two part ring, and having pockets therein in which said rollers reciprocate which rollers divide up said space into chambers, a valve ring, a-

fixed wall, passages leading from said pockets and. from said chambers through said fixedwall to a face over which said valve ring moves, said valve ring separating the RALPH JOHN SMITH.- 

